All of the airports are well mixed. We don’t live in the corn fields of Iowa. The vegetation is fairly uniform across the region. Most of the ASOS differences are due to frontal boundaries, ocean influence, or elevation.
I’m 615ft and my dew is too high usually too. I have a soaked yard with no air mixing. But even the sensors themselves seem to oversaturate in higher dewpoints. Our sensors calculate RH and calculates a dew from that. There’s some error. ASOS directly measures the dewpoint without an all-in-1 temp/hum sensor.
I’m not hot at all. Every night has been fine with the fans…low 70s at the worst. That bedroom temp is a little inflated in the afternoon because it’s on the west side. But I tolerate the warmth and dews just fine. Trust me it’ll go in when we feel like we need it.
They probably mounted the temp probe an inch below the water surface like my dad's pool too so that the sun can beat on it. Then when we would bitch about it being cold he could say it's 85F.